Get nvtool, gtx into backscratcher
Clean *.pyc on 'make clean'
Use util.dispatch in gtx.py, nvtool.py
Add stash and load to nvtool.py

 - Also ignore emacs work files ('.#*')
Document subcommands load and stash
Better message from hook pre-commit
Added gtx, nvtool to setup.py
Update gtx with rm_untrack, other cleanups